The present invention relates generally to circuit modules and, more particularly, to a memory card (e.g., a multi-media card (MMC)) comprising a leadframe which is implanted into a plastic body and provided with stand-off features which are arranged to prevent metal exposure subsequent to the molding of the body of the card.
As is well known in the electronics industry, circuit modules or cards are being used in increasing numbers to provide memory storage and other electronic functions for devices such as digital cameras, MP3 players, cellular phones, and personal digital assistants. In this regard, circuit modules are currently used in various memory card formats, including multi-media cards and secure digital cards.
Typically, circuit modules include multiple integrated circuit devices or semiconductor dies. The dies are interconnected using a circuit board substrate which adds to the weight, thickness, stiffness and complexity of the module. Circuit modules also include electrical contacts for providing an external interface to an insertion point or socket. These electrical contacts are typically disposed on the back side of the circuit board substrate, with the electrical connection to the dies being provided by vias which extend through the circuit board substrate.
In an effort to simplify the process steps needed to fabricate the circuit module and, hence, the memory card using the same, there has been developed by Applicant a circuit module wherein a leadframe assembly is used as an alternative to the circuit board substrate, as described in Applicant's co-pending U.S. application Ser. No. 09/956,190 entitled LEADFRAME METHOD AND ASSEMBLY FOR INTERCONNECTING CIRCUITS WITHIN A CIRCUIT MODULE filed Sep. 19, 2001, the disclosure of which is incorporated herein by reference. As is described in Ser. No. 09/956,190, the leadframe and semiconductor die of the circuit module may be covered with an encapsulant which hardens into a cover or body. The body is sized and configured to meet or achieve a “form factor” associated with the memory card. In the completed memory card, the contacts of the leadframe are exposed within a common surface of the body, with a die pad of the leadframe and the semiconductor die mounted thereto being disposed within or covered by the body.
Applicant has previously determined that the molding or encapsulation process used to form the body of the card sometimes gives rise to structural deficiencies or problems within the resultant memory card. These problems include portions of the die pad of the leadframe being exposed within the memory card, flash being disposed on the contacts of the leadframe, chipping in a peripheral flange area of the body, and mold gate pull-out wherein a portion of the mold or encapsulating compound is pulled out from within the body, leaving a small recess or void therein. To address these particular problems, Applicant has previously developed a memory card having a “die down” configuration attributable to the structural attributes of the leadframe included therein, and an associated molding methodology employed in the fabrication of such memory card. This die-down memory card is disclosed in Applicant's co-pending U.S. application Ser. No. 10/266,329 entitled DIE DOWN MULTI-MEDIA CARD ANI) METHOD OF MAKING SAME filed Oct. 8, 2002, the disclosure of which is also incorporated herein by reference. The present invention addresses and overcomes yet another problem which relates to the tendency of the metal of the leadframe to be pushed down or deflected during the molding operation used to form the body of the memory card. Particularly, in accordance with the present invention, the leadframe is provided with stand-off features which prevent the leadframe from being pushed down during the molding operation, thus substantially preventing undesirable occurrences of portions of the metal leadframe being exposed within the completely molded body of the memory card. These and other attributes of the present invention will be described in more detail below.